Seven speed gearbox - uses three epicyclic trains in various combinations with fourth train for reverse gear

摘要

The change speed gear box uses four trains of epicyclic gears to provide seven forward speeds and one reverse speed. Each epicyclic train (A, B, C, D) can be locked so that its output speed is equal to its input speed. The seven forward speeds are achieved by using any one of the three trains (A, B, or D) alone or by using any pair of these trains or by using all three trains. The epicyclic train (C) is used only for reverse gear. A range of seven different ratios results in smoother gear changing.